Pressure gauge



J. D. DURANT PRESSURE GAUGE Filed March 18, 192% INVENTOR ATTORNEYS;

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This invention relates to gauges for ill-1 ,dicating the de th of liquidin tanks, and i more particular y to gauges oi the typethat are employedfor indicating the depth ofto adjustable means whereb the zero level maybe quickly and accurately determined,

lt is the general purpose and obyect of this invention to provide aange-oi this character with such means; and in the drawan ing formingpart hereof there is shown a detail in section of a gauge constructionwhereby the adjustment referred to may be conveniently obtained, thesystem in which the gauge is used being shown on a smaller goscale atthe right handside oi the view.

Describing by reference characters the various parts shown in thedrawing, 1 de-- notes a tank containing the liquid, the height or depthof which is to be indicated by the as gauge, the tank shown herein beingsuch as is used for gasoline. Extending from the tank is a hydrostaticconduit 2 which is connected at its upper end with a'tube 3, to thelower portion of which is secured, as by at) brazing, the upper end of acontractible and expanslble receptacle 4, the same beingiof bellowsformation. The said receptacle l may be made of any suitablefiexiblemetal or material and has secured to the bottom there-' as of acentral reinforcing plate 5 having a notch 6 for the reception of thepointed upper end or a screw 7, threaded into a bracket 8 which may besecured to the front the top of a cup-like rec'eptac e 12, the bot-- 4etom of which is connected with the lower conduit.

portion ofthe tube 3 by means of a short tube 13 of restricted boreextending horizontally from the 'cup 12 and having its outer endextending downwardly within anl approximately to the bottom of the tn e3.

For the purpose of purging the conduit 2 of liquid and maintaining thesaid conduit :tull ofair, a pump 14 isernployed, the said pumpcommunicating by aconduit 15 witha short conduit 16 which is connected.to

the conduit 2. The conduit 16 is provided with a mercury valve 17therein above its ,point of communication with conduit 15,

the. mercury valve being seated on a porone partition 18, there being aporous dam 19 above the mercury valve to prevent the latter from beingdriven into the conduit 2. The portion of the conduit 16 which extendsbelow the conduit 15 is provided with a similar mercury valve 20 restingon a porous partition 21, there being a porous dam 22 above the saidvalve.

In operation, the parts 3, d, 9, l2 and i3 constitute a U-tube which,when the tank 1 is empty will assume the zero level indicated by thedotted line A-A. When the tank 1 is full, the hydrostatic pressure inthe line 2 will depress the column of liquid in the pipe 1 and theliquid will be raised in the' gauge tube 9 to a point indicated by theline BB, at which time the liquid in the tube?) will fall to a levelindicated by the line CC.

' Should any liquid enter the conduit 2, it will be displaced from timeto time by opcrating the pump 14, which will result in drawing in airthrough the valve 20 and forcing it past the valve 17 into the conduit2, thereby blowing out all liquidfrom. said The endwise contractible andexpansible receptacle l constitutes a simple, effective and'convenientmeans, forming part of the :gauge glass tube, at one side of the firstmentioned tube, a conduit of restricted bore bringing the level of theliquid in the branches 3 and 9 coincident with the zero mark on thescale of the latter tube. Assuming that the liquid in the tank 1 hasfallen to the datum level, then should the level of the liquid in thegauge glass be above the line A--A, this can be readily cured by turningthe screw 7- in the a propriate direction to increase the capacltyofvthe' receptacle 4, until the liquid stands at the desired-level inbotlibranches 3 and 9. Should the liquid level stand below thezero markor indication, then this inaccuracy canbe readi-- l corrected byoperating the screw Tin a direction requisite to decrease the capacityof the receptacle 4. 1

It will be noted that the lower end of the tube 13 extends considerablybelow the line CC, which indicates the lowest level of liquid normallywithin the tube 3. This in- .sures that the lower end of the tube 13will be sealed by liquid under all conditions, even when the pump 14 isoperated to purge the conduit 2. Furthermore, the tube 13, being ofsmall cross sectional area, prevents sudden fluctuations in pressurefrom affecting the column of liquid in the tube 9.

From the foregoing description it will be evident that I have produced agau e which .enables me to secure the results re erred to and economicalof production.

Having thus described my invention, what I claim is:

1. A liquid containing gauge comprising a vertically extending tubeoenat both its ends, an elongated bellowsike receptacle secured at itsupper end to the lower portion of said tube and extending therebelow, a

in sealed communication at one end with the bottom of said an e tube andsealed through one side of t e rst mentioned tube 'at a point above theend thereof and having a portion extending downwardly inside said tube,means engaging. the lower end of said bellows-like receptacle for movingsuch end toward and from the first tube thereby to vary the effectivelength and capacity of said receptacle, and means supporting the variousparts in proper relation to each other.

2. A liquid containing gauge comprising a vertically extending tube openat both its ends, an elongated bellows-like receptacle secured at itsupper end to the lower portion of said tube and extending therebelow, agauge glass tube at one side of the first mentioned tube, a conduit ofrestricted bore in sealed communication at one end with the bottom ofsaid gauge tube and sealed through one side of the first mentioned tubeY at a point above the end thereof and having a portion extendingdownwardly inside sai tube, means engagin the lower end of saidbellows-like receptac e for moving such end toward and from thefirst-tube thereby to vary the effective length and capacity of saidsignature.

JOHN D. DURANT.

